1. Field of the Invention
The invention relates to an improved closure for bags and like flexible containers which seals the bag fluid-tight and gas-tight yet allows easy and rapid reopening of the bag for access to its contents, and to a method directed to such an improved closure. The invention also relates to a fluid-tight and gas-tight bag having an improved leak-proof closure which allows easy and rapid reopening of the bag.
2. Prior Art
It is frequently desirable to have a light, resealable bag that is fluid-tight or gas-tight, either to keep the contents of the bag dry or to prevent liquids or gases from leaking out of the bag. The requirements in a bag for a leak-proof closure, yet one providing easy access to the bag and overall light weight, have a higher premium in more rigorous applications, e.g., cycling or back country hiking. Traditional methods of closure include so-called zip-lock or pressure strips, clamps, clips, and threaded caps. Zip-lock strips have limited durability and often do not form a true gas-tight seal. Expensive molding equipment or tooling may be needed to form these closures. Such a closure may add an awkward element to the bag and access to the contents of the bag may be restricted if the nature of the closure, such as a cap, is narrower or more rigid than the main body of the bag.
Light weight, resealable bags are used increasingly in sporting activities. Limited access to the interior of prior art bags makes cleaning more difficult creating the potential for unsanitary or at least offensive conditions. Once liquid products placed in such sporting bags are consumed, the remaining deposits if not immediately and thoroughly cleaned encourage the growth of bacteria and mold. If left uncleaned, such growths can leave ugly stains on the bag, may tenaciously retain offensive odors, taint any other fluids subsequently introduced into the bag, and can create serious health risks. Regular and thorough cleaning is therefore critical, especially if it is desired to use dairy-based products in the bag. Prior art bags which are truly fluid- or gas-tight do not provide adequate access to their interiors for cleaning.
Many flexible bags have been developed which can be sealed and resealed to close the bag's contents from environmental contaminants. In particular, several closures have been developed which improve the seal by rolling or folding that portion of the bag near the opening back upon itself For example, Dernmis, U.S. Pat. No. 5,816,709, discloses a leak-proof travel bag for carrying items containing liquids, such as toiletry products, while traveling. The Denius bag shows a zip-lock closure for sealing and resealing the opening of a water-proof bag. The bag is closed by sealing the opening with the zip-lock closure, folding the closure strip over once, then again, whereupon it is sealed to the bag using a hook-and-loop-type fastener, and finally sealing the folded-over portion with a flap using a second hook-and-loop-type fastener.
Rinecker, U.S. Pat. No. 3,446,420 discloses a flexible mouth container wherein the mouth of a container having a sheet-like opening is folded over upon itself and secured with a hook-and-loop-type fastener. Similarly, Vani Loan, U.S. Pat. No. 3,203,551 discloses a filter bag including a cover flap to close the bag. The cover flap is folded over and held in place against the bag with a hook-and-loop-type fastener or a plastic zipper and locking tabs. Finally, Latia, U.S. Pat. No. 2,342,406 discloses a fumigant bag which is closed by joining two stiff, but bendable, strips at the mouth of the bag and folding them down together several times where they are secured in place with ties.
While the roll-down style closures have certain advantages over prior art closures, they tend not to form perfect seals and, especially when the contents of the bag are under pressure, the rolled part of the bag may unroll or loosen thereby decreasing the effectiveness of the seal. There is accordingly a need for an improved bag closure which creates a fluid-tight or gas-tight seal yet which is simple to operate, provides easy and rapid opening for access to the contents of the bag, is light weight, and is inexpensive to manufacture.